Herbicidal formulations



Patented Apr. 24, 1951 UNITED STATES PATENT OFFICE 2,550,049 7 HERBICIDAL FORMULATIONS poration of Delaware No Drawing. Application January 3, 1950, Serial No. 136,664

8 Claims. 1

This invention relates to herbicidal formulations; more specifically, this invention relates to improved herbicidal formulations comprising a derivative of trichloroacetic acid.

Of the various types of formulations employed in the prevention and growth or the destruction of weeds, aqueous emulsions having one or more active herbicides dissolved or dispersed therein are most frequently utilized. Such emulsions offer many advantages. For example, from the standpoints of shipping and application, the active herbicides or a concentrate containing the same may be shipped directly to the area of application and diluted and/or emulsified with water immediately prior to application.

Oils are also generally employed in herbicidal formulations and the oils per se may be active herbicides. The inclusion of oils also permits a better contact between the weed or plant to be eradicated and the active herbicide present in the emulsion.

The salts of trichloroacetic acid have a recognized utility as selective herbicides. It is impossible, however, to prepare stable oil-in-water herbicidal emulsions containing such salts of trichlororoacetic acid. The salts are not soluble in oil and, hence, can not be dissolved in the oil phase of such an emulsion. It has further been found that the salts of trichloroacetic acid are excellent aqueous emulsion breakers. It is, therefore, impossible to prepare stable and permanent oil-in-water type herbicidal emulsions having salts of trichloroacetic acid dissolved or dispersed in the aqueous phase of such an emulsion. Consequently, heretofore it has not been possible to prepare a stable oil-in-water type emulsion havin incorporated therein as one of the active herbicides, such a derivative of trichloroacetic acid as a salt thereof.

It is an object of this invention to provide an improved herbicidal formulation employing a derivative of trichloroacetic acid as one of the active ingredients.

It is a further object of this invention to provide an improved herbicidal formulation comprising an oil and a derivative of trichloroacetic acid.

Another object of this invention is to provide an improved herbicidal formulation comprising an oil-in-water type emulsion having dissolved or dispersed therein, a derivative of trichloroacetic acid.

Further objects of this invention will become apparent from the description of the novel compositions which follow.

It has now been discovered that an alkyl ester of trichloroacetic acid having the formula 01 0 R1 01- J- -0 oH wherein R1 and R2 represent alkyl radicals which together contain not more than '7 carbon atoms, or a solution thereof in oil may be emulsified into a substantially permanent oil-in-water type herbicidal emulsion. As a result of this invention, it is, therefore, now possible to prepare herbicidal formulations comprising an aqueous emulsion of a derivative of trichloroacetic acid, either as the sole active herbicide or together with other oil soluble selective herbicides, and/ or herbicidal oils. The following examples are typical of the outstanding herbicidal formulations that may be prepared in accordance with the teachings of this invention:

' Example I pounds of isopropyl trichloroacetate were combined by mechanical mixing with 75 pounds of oil and 7.5 pounds of a suitable oil soluble emulsifyin agent to form a stable emulsifiable concentrate. The resulting concentrate is emulsified with 200 gallons of water to form an exceptionally stable oil-in-water emulsion formulation. After spraying this emulsion substantially uniformly over a one acre tract of grassy, weedcovered land, the leaves and stalks of the plants are found to be completely killed within a few days.

Example II 3 pounds of pentachlorophenol are dissolved in 5 gallons of an aromatic oil and emulsified with 2.5 gallons of water with the aid of a suitable emulsifying agent to form a concentrated oilin-water emulsion. Thereafter, 12.5 pounds of isopropyl trichloroacetate are added and then about gallons of water are incorporated with stirring. The resulting emulsion is found to have a stability comparable to the product of Example I and a high degree of herbicidal activity.

Example III 2 pounds of pentachlorophenol are dissolved in 5 gallons of oil and emulsified with 2.5 gallons of Water with the aid of a suitable emulsifying agent to form a concentrated oil-in-Water emulsion. Therefore, 2 pounds of the isopropyl ester of 2,4-dichlorophenoxyacetic acid and 10 pounds of isopropyl trichloroacetate are added and then about 200 gallons of water are incorporated with 3 stirring. The resulting emulsion is comparable with the product of Example II in stability and herbicidal activity.

Example IV Example V Example III is repeated exceptthatia stoichiometrically equivalent amount of 'l methylhept'yl trichloroacetate is substituted for isopropyl trichloroacetate. A generally siniilar prodnctxiis obtained. 7

7 Example VI 5 pounds of an oil soluble emulsifying agent is ;dissolved in 100. poundsuof. isopropyl :trichloroacetateto form. anemuls'ifiable concentrate-which is then dispersed with agitation in 250 gallons of water. A highly active herbicidal emulsion of remarkable stability results.

The esters of trichloroacetic acid utilized in -;the novelcompositions of this..-invention may .aloe :conveniently prepared by'esterifying .trichloro- :acetimacid with :asecondary .alcohol containing .at least 3 .and-not more than 8 carbon atoms.

Whilethe-use of isopropyl.trichloroacetate represents a preferred embodiment ofthis invention,

. fthe. following alkyl-etrichloroacetates are illustrative. of the compounds whichmay. be utilized vinithe novel cm-p0sition5.=0f this invention:

Secondary .butyl trichloroacetate lemetm'lbutyl trichloroacetate 1,2 1-;dimethylprppyl 'trichloroacetate "1 -ethylpropyl trichloroacetate l-methylpentyl trichloroaoetate l-ethylbutyl trichloroacetate zleethyle'zemethylpropyl trichloroacetate 1.,3L-dimethyLlbutyl trichloroacetate 5 1,2-dimethylbutyl-ztrichloroacetate ;-..=1'-methyl-2-ethylbutyl trichloroacetate Lleisopropylbutyl.trichloroaoetate :leethyl-B emethylbutyl trichloroacetate l emethylFl methylpentyl =trichloroaoetate .1..-1ethyl-2-methylbutyl. :trichloroacetate Lemethylhexyl trichloroacetate j1-pr0pylbutyl trichloroacetate lemethylheptyl trichloroacetate In contrast to the outstandingly stable oil-inwater type emulsions which may be prepared in in accordance with the teachin s 3 of thisinvention. Three concentrated herbicidal emulsions were prepared, each "containing the following =r common ingredients:

.. 1.gallon of an aromatic oil having .a boiling point .withintherange of 360"F. to 620 F.

.. PX; gallon water 10.6 lb. of pentachlorophenol 0.1.1'lb. of an emulsifier containing 177% by Weight of sodiumdodecylbenzenesulfonate vanci'23 72 193 merely 'shaking the formulation.

weight of a sodium petroleum (mahogany) sulfonate.

In addition, the first emulsion contained 2.58 lbs. of ethyl trichloroacetate. The second emulsion contained 2.79 lbs. of isopropyl trichloroacetate, and the third emulsion contained 2.96 lbs.

.of .;butyl f-trichloroacetate. I The. above yprepared concentrated herbicidal emulsions were allowed to stand and the lapse of time before the emulsion broke noted. It was found that the emulsion -,containing- .the ethyl trichloroacetate broke in approximately 8 days and could not be re-emulsified. *The emulsion containing the butyl trichloroacetate broke in approximately 10 days "and c'ou1d"n'ot"be re-emulsified. However, the aemulsioncorrtaining isopropyl trichloroacetate zdidhot begin to break until the elapse of approximately 21 days, and could be r'e-emulsified by It was also found that an oil-in-water type emulsion identical to those described above except that it contained" 2.5 1bs.' o'f sodium trichloroacetate (which =ris equivalent to 2;7-9 lbs.-of isopropyl *tr-ichloroacetate) in place of an ester of trich'loroac'etic 3JC1d,lblOk almost immediately after' formation.

:Itiis clearly; evident from these data that isopropyl :trichloroacetate possesses an outstanding'hydro- .:lyt1c 'stability'which [permits the preparation'c :stable herbicidal emulsions.

When the novel herbicidal formulations of this invention. :contain .oils, there 'may be used anyzof the :common oil-ibases, such. as Diesel o'i-ls,

. :mineraloils. ,fuel oils, pine oil -andaroma'tic oils, ssuch asithose aromatic oils boiling within the range 011769? F.::to .760" E, or those oils "which are aromatic :in natureiand containat least 15% .of aromatic. hydrocarbons :boilingwwithin the rangepf 176MB. and 760931. .Typical examples .of .theseuaromatic .hydrocarbonzoils.:are benzene, toluene, ethylbenzene, ;.;xyl,ene, :alkyl .naphthalenes such as the methyl substituted Lnaphthalenes,- qethylnaphthalenes, 18136., and mixtures of oils containing :these .and/or other aromatic hydrocarbons. These herbicidal noil formulations may also have'dissolved therein anyxof the commonly used oil soluble herbicidal agents well known to those. skilled in the art, such as the fi yiilg agents,..su.ch as .the alkyl .aryl sul- .-fonates, of which-sodium dodecylbenzenesulfo- .nate is .a particular example, sulfated fatty .alcohols, alkyl sulfonates, sulfated esters and .acids, amide sulfates and sulfonates, sulfated and sulfonated oils, fats, and .waxes, fatty esters of glycerol and glycol and other polyhydric alcohols, such as .sorbitol, .the condensation products of ethylene oxide with fatty acids, abietic acid, alkyl phenols, such asnonyl phenol, andmercaptans, suchas tert..-.dodecyl mercaptan, etc, as well asmixturesof these and/or other surface-active agents.

Emulsifiable concentrates of the trichloroacetic acid. esters of. .theinvention may be prepared. in various forms as indicated by the examples, e. g. solutions of the esters .in oil bases, solutions of emulsifying agents in the esters and concentrated oil-in-water emulsions containing the esters, etc.

The concentration of the alkyl trichloroacetate in the oil-base formulation may be varied over a wide range. The concentration utilized is governed by the herbicidal activity desired, the concentration desired in the finished emulsion formulation, and the solubility of the alkyl trichloroacetate in the particular oil base utilized. For most purposes, a concentration within the range of from about to about 75% by weight of the alkyl trichloroacetate based on the oilalkyl trichloroacetate solution has been found most satisfactory.

Dilute herbicidal emulsions may be prepared from the emulsifiable concentrates or concentrated emulsions of this invention by simple dilution accompanied by stirring or other agitation of the mixture of concentrate and water. Such herbicidal emulsions may be prepared at the site of application or may be prepared in advance and transported to the site of application in the form of finished emulsions. Preferably, however, for convenience and economy, the emulsions are prepared immediately prior to use. The amount of the alkyl trichloroacetate contained in the dilute emulsions may be substantially varied depending at least in part on the use to which the emulsion is to be placed. Usually from 0.05 to 10% of the ester is used based on the weight of the entire emulsion.

What is claimed is:

1. An improved herbicidal composition comprising an oil, an emulsifying agent, and an alkyl trichloroacetate having the formula wherein R1 and R2 represent alkyl radicals which together contain not more than 7 carbon atoms,

said composition being emulsifiable with Water to form a stable emulsion.

2. The composition as described in claim 1 wherein the alkyl trichloroacetate is iscpropyl trichloroacetate.

wherein Brand R2 represent alkyl radicals which together contain not more than 7 carbon atoms.

6. The composition as described in claim 5 wherein the alkyl trichloroacetate is isopropyl trichloroacetate.

7. The composition as described in claim 5 wherein the alkyl trichloroacetate is sec.-butyl trichloroacetate.

8. The composition as described in claim 5 wherein the alkyl trichloroacetate is l-methylheptyl trichloroacetate.

CHARLES M. EAKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,393,086 Bousquet Jan. 15, 1946 2,396,513 Jones Mar. 12, 1946 OTHER REFERENCES Science, July 25, 1947, page 87.

Science, July 23, 1948, pp. and 86. Science, July 30, 1948, pp. 112 and 113. Science, Sept. 10, 1948, pp. 278 and 279. 

1. AN IMPROVED HERBICIDAL COMPOSITION COMPRISING AN OIL, AN EMULSIFYING AGENT, AND AN ALKYL TRICHLOROACETATE HAVING THE FORMULA 